The goal of this project is to develop a computerized screening program for primary care offices that is based on the NIAAA's Alcohol Screening Guide for Children and Adolescents and assess its psychometric properties among nine- to 18-yr-old primary care patients. There is substantial evidence supporting the effectiveness of screening and brief intervention among adult primary care patients, primarily in the reduction of harmful drinking. However, there have been few studies of alcohol screening and brief intervention conducted among adolescents receiving primary medical care. This project will develop and validate a new computerized Alcohol Screening for Children and Adolescents (cASCA) system based on the two age-specific screening questions of the NIAAA Guide and includes the CRAFFT and AUDIT as secondary risk and problem assessments. We will add tobacco screening, because tobacco use is the leading cause of cancer-related mortality in the US. The system will yield a provider report with the screening results, level of risk, and recommended brief advice, counseling, or referral strategies. The Specific Aims of this project are to: 1. Assess the sensitivity, specificity, positive and negative predictive values of the 'any drinking/number of drinking days' and 'friends' questions of the cASCA in identifying past-year use as determined by the Timeline Follow-Back Calendar (TLFB), and for identifying any problem use, abuse or dependence as determined by the AUDIT, CRAFFT and a structured psychiatric diagnostic interview (computerized DISC- IV, Youth Version) at baseline (criterion validity). 2. Assess the test-retest reliability of the cASCA in measuring drinking frequency categories and in classifying patients into Low, Medium and High risk categories. 3. Assess the predictive validity of the 'any drinking/number of drinking days' and 'friends' questions in predicting drinking, binge drinking, and any problem use, abuse or dependence at 12-mos follow-up. 4. Assess the degree to which the 'any drinking/number of drinking days' item of the cASCA predicts drug use risk as measured by the TLFB (any use and frequency), tobacco use as measured by the Hooked on Nicotine Checklist (screen for potential nicotine dependence), drug use disorders as measured by the Drug Abuse Screening Test for Adolescents, and the degree to which it predicts other mental health problems as measured by the Youth DISC Predictive Scales at baseline and 12-month follow-up. 5. Compare the psychometric properties of the cASCA across subgroups, including: age, gender, race/ethnicity, practice type, provider type, and patient risks (e.g., those with/without friends who drink); and explore the possible effects of the cASCA system on drinking at 3-, 6-, 9-, and 12-month follow-ups.